1. Field of the Invention
The invention relates to the assembly and structure for providing electron discharge tube anode members which utilize castings and electrical contacts made by nonthermal techniques.
2. Description of the Prior Art
A well known microwave energy generator is the crossed field magnetron device incorporating a central cylindrical cathode encircled by a plurality of cavity resonators defined by vane members extending from common boundary wall member of an anode member. An external magnetic field is applied parallel to the axis of the cathode member while an electric field is established transverse between the cathode and anode members to thereby provide crossed electric and magnetic fields. Typically, in such devices electrons are emitted from an electron emissive cathode into an annular interaction space between the cathode and anode members. Under the influence of the crossed electric and magnetic fields a revolving spoke-like space charge provides electronic interaction and oscillations at the very high frequencies.
Commonly the anode member comprises a circumferentially disposed anode cavity resonator system defined by a plurality of anode elements in the form of substantially flat vane members. These vanes are joined at their base portions to a cylindrical common boundary wall member with the free ends extending into the annular interaction region. Single or double conductive metallic straps are connected to alternate vane members to further enhance the efficiencies of the cavity resonator system. One period of the anode member is bounded by two vane members and is referred to as a cavity resonator. The magnetron oscillator may be operated under pulsed or continuous wave conditions and commonly generate the high frequency oscillations in the so-called "pi-mode" which are then coupled inductively to a loop in one of the cavity resonators of the anode member. Such devices are either tunable or fixed tuned.
The magnetron is the widely used power source for microwave cooking ovens which in recent years have become more widely accepted in home and industrial applications. The magnetrons utilized in the microwave ovens have undergone numerous modifications in the interest of compact packaging, as well as lowering costs in these applications. The component which utilizes the most metal and comprises a substantial percentage of the overall tube package is the anode member defining the circumferentially disposed cavity resonators. Conventionally, these members are fabricated of a high conductivity oxygen-free copper and the radially disposed vanes are assembled by well-known brazing and welding metallurgical techniques. Expensive metals, such as gold and silver, are typically utilized for the brazing alloys. New and novel anode fabrication techniques including the use of other materials will further advance the state of the art particularly in the microwave cooking applications.
For the purposes of the present specification and to assist in an understanding of the invention the term "magnetron" is utilized to denote the entire assembly including the anode and cathode, as well as the external magnets, pole pieces, cooling structures and output coupling means. The term "nonthermally" refers to metallurgical techniques for providing intimate electrical contact between two components without heating, such as welding and brazing, and includes cold welding and interference fits to unite the components.